Adapter



FIG. 1 is a top, front, left side perspective view of an adapter showing my new design;

FIG. 2 is a bottom, front, right side perspective view thereof;

FIG. 3 is a front elevation view thereof; and,

FIG. 4 is a rear elevation view thereof.

The equal-length broken lines depict portions of the adapter that form no part of the claimed design. 

CLAIM The ornamental design for an adapter, as shown and described. 